GB798927A - Improvements in and relating to broad band magnetic tape recording and reproduction - Google Patents
Improvements in and relating to broad band magnetic tape recording and reproductionInfo
- Publication number
- GB798927A GB798927A GB26638/55A GB2663855A GB798927A GB 798927 A GB798927 A GB 798927A GB 26638/55 A GB26638/55 A GB 26638/55A GB 2663855 A GB2663855 A GB 2663855A GB 798927 A GB798927 A GB 798927A
- Authority
- GB
- United Kingdom
- Prior art keywords
- frequency
- heads
- output
- recorded
- supplied
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/76—Television signal recording
- H04N5/91—Television signal processing therefor
- H04N5/92—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/76—Television signal recording
- H04N5/78—Television signal recording using magnetic recording
- H04N5/782—Television signal recording using magnetic recording on tape
Abstract
798,927. Magnetic recording and reproducing systems. AMPEX CORPORATION. Sept. 16, 1955, No. 26638/55. Class 40 (2). [Also in Group XL (b)] Television signals are recorded on a magnetic record medium as frequency modulations of a carrier wave, the centre frequency of which is near the maximum frequency which can be recorded on the medium (for a given relative velocity between the medium and the recording heads). In one embodiment (Fig. 1), the signals to be recorded are supplied via a modulation levelcontrol unit 125 to a, variable reactance tube 126 which frequency modulates an oscillator 127 operating at about 45 mc/s. and the output from which, after amplification in 128, is converted to a frequency of about 4 mc/s. in mixers 129 and the output of the latter supplied via amplifier 130 to four channel amplifiers 121 ... 124 which feed, via switch S2, individual magnetic transducer heads in housing 28. These heads, the construction of which is also described in Specification 798,928 (see Group XXXVII), are rotated at high speed by means of a motor 23 so as successively to "scan," transversely to its length, the magnetic recording tape 11, the latter being moved from left to right by means of a capstan 17 driven by a second motor M. To ensure a constant relative speed between the rotation of the heads and the movement of the tape and to compensate for mechanical deficiencies especially slippage of the driving belt 56, the speed of both motors is controlled by means of a photo-electric pulse generating device 24 operated by the shaft which rotates the heads. As shown in Figs. 8 and 9, this device comprises a circular member 61. rotated (with the heads) by means of shaft 31 and the periphery of which is provided with reflecting segments L1, L2 and non-reflecting segments D1, D2 so that, as the shaft rotates, light from a source 66 is reflected from segments L1, L2 on to a photo-electric cell 67 and produces a square-wave form signal of frequency dependent on the speed of rotation of shaft 31 and therefore dependent on the speed of the heads. During recording this signal is supplied, via a cathode-follower stage 71, represented in Fig. 1, by CF, to a filter 81 which converts it into a sine wave of the same frequency and this is supplied via amplifier 82 to a fixed transducer head 19 which records the signal as a control frequency on a marginal portion of the tape. The output of CF is also supplied to a divider 77 which reduces the square-wave frequency to the nominal frequency of a local source (e.g. electric mains) 93 and the output of the divider, after conversion to sine-wave shape in filter 78 supplied, firstly, via switch S1 (in the position shown) to a power amplifier 79, the output of which supplies driving power for the capstan motor M and, secondly, to a phase comparator 87 in which it is phase compared with the local source 93, the output of comparator 87 being employed to control the frequency of an oscillator 84 which supplies, via amplifier 83, the driving power for the head motor 23. During " play-back " (the tape having been rewound from spool 13 on to spool 12) the motor 23 is controlled as described above for the recording cycle, but the capstan motor M is now controlled by varying the frequency of an oscillator 96 in accordance with the output of a phase comparator 99 in which the phase of the output of filter 81 is compared with the already marginal recorded control signal, this being derived via transducer 19 and amplifier 103. The output of oscillator 96 is then supplied, with switch S1 in the opposite position to that shown, to amplifier 79 and thence to motor M. The recorded frequencymodulated television signals are derived via the rotating heads 28 and supplied., with switch S2 in the opposite position to that shown, to preamplifiers 131 ... 134, the outputs of " alternate " ones being combined in mixers 136, 137 and supplied via respective amplifiers 138. 139 to switching circuit 141, 142 controlled by a signal derived from the pulse generator device 24 so as to pass the outputs of amplifiers 138, 139 alternately to a limiter 143. The limiter output is then converted to an I.F. frequency in mixer 144 and., after further limitation in 148, is fed to a discriminator 149 which supplies the originally recorded television signals to the output circuit. In order to ensure that all information is recorded the width of the tape 11 is made greater than the circumferential spacing of the rotating heads (four heads spaced 90 degrees apart) and since this results in duplicate information being recorded on the marginal portions of the tape, erase heads 18, 20 are provided on each side, the former " clearing " the margin to allow the recording of the control frequency signal via head 19, and the latter " clearing " the opposite margin so that other information, e.g. sound signals, may be recorded via head 21. Because of the increased tape width, the switching operation of channel amplifiers 138, 139 must be arranged so that only the desired information is passed to the limiter 143. Such switching arrangements may be dispensed with and the combined outputs of the channel amplifiers supplied to the limiter 143 with some sacrifice in performance (Fig. 2, not shown). The connections to the operating coils of the (four) rotating heads may be made via individual slip-rings (Fig. 10, not shown) or the coils may be connected in series (Fig. 11, not shown) or in series-parallel combinations (Fig. 14, not shown) so that only two slip-rings are necessary. Instead of employing an (sine wave) oscillator such as 127 (Fig. 1), the frequency modulated carrier may be produced by controlling the frequency of a multivibrator by means of the signals to be recorded (Fig. 14, not shown). In all embodiments, the ratio of the frequency deviation corresponding to the maximum signal amplitude to the highest modulating frequency is of the order of 0.2. The Specification includes circuit details of the phase-comparators (Fig. 13, not shown), the frequency modulated multivibrator (Fig. 15, hot shown) and the switching circuits 141, 142 with reference to Fig. 16 (not shown). Specifications 798,929 and 798,930 also are referred to.
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US524004A US2956114A (en) | 1955-07-25 | 1955-07-25 | Broad band magnetic tape system and method |
GB26638/55A GB798927A (en) | 1955-07-25 | 1955-09-16 | Improvements in and relating to broad band magnetic tape recording and reproduction |
DEA23541A DE1034684B (en) | 1955-07-25 | 1955-10-10 | Method and device for recording a broadband frequency spectrum on a magnetic carrier |
FR1137617D FR1137617A (en) | 1955-07-25 | 1955-10-11 | Electromagnetic tape installations |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US524004A US2956114A (en) | 1955-07-25 | 1955-07-25 | Broad band magnetic tape system and method |
GB26638/55A GB798927A (en) | 1955-07-25 | 1955-09-16 | Improvements in and relating to broad band magnetic tape recording and reproduction |
DEA23541A DE1034684B (en) | 1955-07-25 | 1955-10-10 | Method and device for recording a broadband frequency spectrum on a magnetic carrier |
FR1137617T | 1955-10-11 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB798927A true GB798927A (en) | 1958-07-30 |
Family
ID=44718930
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB26638/55A Expired GB798927A (en) | 1955-07-25 | 1955-09-16 | Improvements in and relating to broad band magnetic tape recording and reproduction |
Country Status (4)
Country | Link |
---|---|
US (1) | US2956114A (en) |
DE (1) | DE1034684B (en) |
FR (1) | FR1137617A (en) |
GB (1) | GB798927A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1207442B (en) * | 1962-08-24 | 1965-12-23 | Loewe Opta Ag | Magnetic head assembly |
Families Citing this family (30)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3005056A (en) * | 1956-02-02 | 1961-10-17 | Columbia Broadcasting Syst Inc | Recording reproducing system |
DE1268184B (en) * | 1958-08-04 | 1968-05-16 | Ampex | Magnetic tape apparatus for recording and reproducing broadband signals, in particular color television signals |
DE1272338B (en) * | 1958-08-08 | 1968-07-11 | Ampex | Magnetic tape recording system, particularly for television signals |
FR1234095A (en) * | 1958-09-16 | 1960-10-14 | Fernseh Gmbh | Method and devices for recording television signals on magnetic tape |
NL247479A (en) * | 1959-01-19 | |||
DE1292876B (en) * | 1959-02-18 | 1969-04-17 | Philips Patentverwaltung | Arrangement for recording and playing back measurements using a magnetic recorder |
US3071644A (en) * | 1959-03-26 | 1963-01-01 | Rca Corp | Control systems |
DE1162402B (en) * | 1959-04-27 | 1964-02-06 | Rca Corp | Device for regulating the speed of a rotating magnetic head arrangement in a magnetic tape recorder working with transverse recording, preferably intended for recording or reproducing television signals |
GB893133A (en) * | 1959-06-18 | 1962-04-04 | Bush And Rank Cintel Ltd | Recording of signals on magnetic tape |
DE1132181B (en) * | 1959-09-11 | 1962-06-28 | Fernseh Gmbh | Device for magnetic recording and simultaneous reproduction of signals with a large bandwidth, in particular video signals |
NL256401A (en) * | 1959-10-02 | |||
DE1256248B (en) * | 1959-10-02 | 1967-12-14 | Fernseh Gmbh | Method for the transmission of a television signal via a transmission medium whose frequency range is not significantly greater than that of the television signal, in particular via a magnetic memory |
NL246245A (en) * | 1959-12-09 | |||
GB962441A (en) * | 1960-03-07 | 1964-07-01 | Sony Corp | A magnetic recording and reproducing device |
DE1158550B (en) * | 1960-05-16 | 1963-12-05 | Tokyo Shibaura Electric Co | Device for the magnetic recording and reproduction of high frequency signals |
DE1238504B (en) * | 1960-07-07 | 1967-04-13 | Fernseh Gmbh | Method for storing television signals in which a tape-shaped memory is written on by a writing beam consisting of a stream of electrically charged particles |
NL271579A (en) * | 1960-12-22 | |||
NL126728C (en) * | 1961-05-18 | 1964-11-10 | ||
DE1154825B (en) * | 1961-05-26 | 1963-09-26 | Bosch Gmbh Robert | Method and device for reproducing signals recorded on storage media, in particular image signals, with the aid of electron beams |
NL283136A (en) * | 1961-09-12 | 1900-01-01 | ||
DE1230451B (en) * | 1961-11-30 | 1966-12-15 | Loewe Opta Gmbh | Device for recording and reproducing high-frequency and audio-frequency vibrations, in particular a mixture of television signals |
DE1231749B (en) * | 1961-12-12 | 1967-01-05 | Loewe Opta Gmbh | Method and arrangement for phase control of synchronous reaction motors in television picture recording and reproducing systems |
US3270130A (en) * | 1962-03-27 | 1966-08-30 | Rca Corp | Servo system with plural reference signals |
US3392234A (en) * | 1962-10-08 | 1968-07-09 | Matsushita Electric Ind Co Ltd | Broad band magnetic tape system |
DE1259932B (en) * | 1963-11-13 | 1968-02-01 | Rank Bush Murphy Ltd | Apparatus for reproducing television signals recorded on magnetic tape |
US3342951A (en) * | 1964-04-20 | 1967-09-19 | Ampex | Servo control system and method in a helical scan recorder |
US3350504A (en) * | 1964-08-10 | 1967-10-31 | Victor Company Of Japan | Frequency modulated magnetic recording and reproducing system |
US4591930A (en) * | 1983-09-23 | 1986-05-27 | Eastman Kodak Company | Signal processing for high resolution electronic still camera |
US8352400B2 (en) | 1991-12-23 | 2013-01-08 | Hoffberg Steven M | Adaptive pattern recognition based controller apparatus and method and human-factored interface therefore |
US7966078B2 (en) | 1999-02-01 | 2011-06-21 | Steven Hoffberg | Network media appliance system and method |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2245286A (en) * | 1936-06-26 | 1941-06-10 | Marzocchi Luigi | Electromagnetic sound recording |
US2461368A (en) * | 1944-12-19 | 1949-02-08 | Philco Corp | Magnetic transducing apparatus utilizing a helical sound trace |
US2604321A (en) * | 1948-08-20 | 1952-07-22 | Brush Dev Co | Magnetic recording and reproducing |
US2648589A (en) * | 1949-07-19 | 1953-08-11 | Bell Telephone Labor Inc | Magnetic recorder |
US2641656A (en) * | 1950-05-17 | 1953-06-09 | Robert H Dicke | Sound recording and reproducing apparatus |
US2612566A (en) * | 1951-06-05 | 1952-09-30 | Bell Telephone Labor Inc | Magnetic recording and reproducing system |
US2668283A (en) * | 1951-08-20 | 1954-02-02 | John T Mullin | Frequency compensation method and apparatus |
US2867685A (en) * | 1952-02-18 | 1959-01-06 | Minnesota Mining & Mfg | Television recording and reproducing system |
DE927999C (en) * | 1953-07-01 | 1955-05-23 | Telefunken Gmbh | Apparatus for magnetic recording and reproduction of television images |
-
1955
- 1955-07-25 US US524004A patent/US2956114A/en not_active Expired - Lifetime
- 1955-09-16 GB GB26638/55A patent/GB798927A/en not_active Expired
- 1955-10-10 DE DEA23541A patent/DE1034684B/en active Pending
- 1955-10-11 FR FR1137617D patent/FR1137617A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1207442B (en) * | 1962-08-24 | 1965-12-23 | Loewe Opta Ag | Magnetic head assembly |
Also Published As
Publication number | Publication date |
---|---|
DE1034684B (en) | 1958-07-24 |
US2956114A (en) | 1960-10-11 |
FR1137617A (en) | 1957-05-31 |
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